I recently purchased a 5.56mm laser pointer that that is sold on Amazon as a “Laser Zeroing Bore Sighter” for firearms to allow me to more-accurately zero X/Y in the center of a workpiece, as the eyeball method has not yielded the best results. I simply mount the laser pointer in a collet and gently snug it up on the spindle–this, to me, seemed like an economic alternative to some of the laser pointer options for CNC machines that are out there.
The pointer sits very snug in the collet–there is no play in it whatsoever. I also push it all the way up so the length of the bore sighter is engaged in the collet. My first 2 uses of this worked perfectly yesterday, but I noticed that as I rotate my spindle, the laser isn’t in the exact center–it’s as if the end of the spindle is off slightly (by a few thousandths) in each direction during each 90-degree rotation.
I approximated the center of the 4 dots to line up with the mark on my workpiece to compensate, but could my spindle be bent or is this normal (i.e., play in the collet or due to manufacturing tolerances of the spindle itself)? The machine came with a RatttMotor Spindle / VFD. It has the drill marks on the spindle nut showing that it was balanced, so it seems odd that they would go through the trouble to balance it with it out of spec.
I plan to get an arm for my dial indicator so I can see if the spindle shaft is, in fact, bent, but I wasn’t sure if anyone else has experienced this.
I went with the green because AI told me it would show up better in wood.
The only thing that’s a bit of a pain is there is no on/off button–you remove the battery to turn it off. It does come in a case with 3 batteries so it isn’t that much of an inconvenience. So far (2 cuts in), I’m happy with it.
i ordered a different one. but thank you I am looking forward to using it as i am one of those guys that used the center of my projects a lot more than a corner. Just a habit, but I like it better. Corner to corner pencil an x and then set work zero.
Thanks for the response–you’re right, at 18K+ RPM, a bent spindle would be obvious (if not destructive).
I ordered a base / arm for my dial indicator just to be sure. Not that I needed one, of course, but I’ve always wanted one and have needed one on occasion over the years.
I’ve never seen a cheap laser that was concentric with it’s body. If you want to see how bad it really is, lay it in a vee block and focus on something 10 ft away and then rotate it. It will look like that icon on your computer screen that chases it’s tail…
It does need to be trammed–I never considered that would show up in the laser dot, but it makes sense. I have 1 more job to finish tomorrow and then I’ll tram it.
I believe it will, but the only way you would be able to tell is if the laser beam/dot and laser housing axes were perfectly colinear. There are methods to do this that use a mirror, but it takes a lot of time and adjust/recheck repetition.
If this condition were true, and your spindle was perfectly trammed, the dot would stay in the exact same spot regardless of spindle Z height changes.
If there was nod or tilt present, the dot would change location with spindle height position.
I do not believe the discussion was suggesting the use of a laser as a tramming method. As to needing 10 feet to be observable, I imagine that depends on the qualities of the beam/dot size, ones ability to accurately record is position(s), and how large the nod/tilt is.
I appreciate everyone’s opinion here but to call my solution “absurd” is a bit harsh. Though I don’t need to explain my reasons to some keyboard warrior, I will anyway for anyone ELSE that struggles with my situation and likes to use technology to help solve it. For context:
My reasoning for doing this is to perfectly (or as close as possible) line up my spindle in the exact center of my work piece (the work piece is 15” round)
My secondary goal is repeatability, as I plan to make a few of these items each month (I am working on the 4th and 5th ones now)
I’ve tried using an end mill to line up X/Y to a pencil crosshair on a piece in the past and I messed up the piece which was frustrating
Always looking to improve, I then thought of using a 30-degree V-Bit’s point to accomplish the same thing–except there are shadows under my spindle and with the back half of the dust boot on and my machine being 48” X 48”, it’s really difficult to see if the Y axis is aligned with the work in the center of the spoil board
Given differences in lighting conditions, the angle of my eyes when looking, etc., I also am concerned about the repeatability of my process so I was looking for something that would be consistent each time
I suppose I could buy a drill blank or use something like a 1/4” center punch in the collet, or repurpose a broken end mill (luckily I don’t have any yet) for this purpose, but that doesn’t solve the shadow issue or not being able to see very well for the Y axis alignment. I suppose I could also buy a ring light to put under the spindle and remove the dust boot each time, too, but then, I still would need to be very consistent each time I align it by eye as looking from different locations could change my perspective of where center actually is and ruin the piece. (Ask me how I know this.)
OR, I could just use a $20 laser pointer to accomplish the same thing with less cost, less complexity (no ring lights to wire, etc.), fewer manual steps (like not having to remove the dust boot), and more consistency / better repeatability.
Another added benefit of my “absurd” solution is you don’t have to lower the spindle all the way down on your work piece to align it perfectly, as the laser pointer dot is consistent from any Z height (assuming your machine is trammed properly). This also saves the time it takes to manually jog the z axis down to the workpiece like if you were using a V-bit.
The only “negative” I see here is the laser isn’t 100% aligned in the center of its housing (read above for why)–it is off by maybe a thousandth or two to one side. For firearm use, it’s fine–as the dot would be close to the center of the bullet regardless. For me, I aim for a bit more precision so to solve for this, I rotate the spindle in 90-degree increments and center the spindle so the laser dot is equal from left to right and front to back over my pencil crosshair. This takes 20 seconds at most.
I thought this forum was meant to help people, not knock someone down for trying something different. Stay classy, folks.
Otis, I didn’t mean to ruffle your feathers nor refer to your method as “absurd”. The “absurd” comment was reference to the conversation about checking tram with a laser and kinda going off subject and not answering your question. Now that you gave more context on the situation, one can give you more specific advise. I have no idea how precise your center position has to be, hence the question about a laser. Laser dots will vary in size, but in general, used on an application like this I’d say it doesn’t have to be NASA precision. Even laser lights on miter saws are over 1/16" wide. If that is good enough for the job, use it.
You also mentioned that the work piece is 15" in diameter. Is there some valid reason that it has to be smack dab in the middle of the spoil board? I like to put my work closest to where I have a good visual and where the clamping method works the best.
When I do similar jobs like clock faces, I drill the center hole first and zero from that.
I don’t know how accurate you need to be but I would make a square fixture with a hole in it that matches the part plus a few thousand so it’s a snug fit.
On the fixture I would have x and y marked with a V bit for alignment to the same lines grooved into the table
The table grooves would be referenced from the home 0,0 so it can be repeated
If that’s not acceptable use a wobble edge finder like machinists use in a mill.
That’s really accurate
I mounted a laser pointer on the side of the spindle mount and used an offset (mach 3) to move the head over once the laser was over the centre mark, it worked OK but was not always perfect as the laser was not the best quality in my opinion. I may try again with a better quality laser in the future.
